Flat glass is heated to its softening point (approximately 600-700°C) and formed into a curved shape under its own weight or with the aid of a mold. It is then rapidly and uniformly quenched (tempered),creating safety glass with a specific radius of curvature.
Curved Tempered Glass / Bent Tempered Glass
Core Process: Flat glass is heated to its softening point (approximately 600-700°C) and formed into a curved shape under its own weight or with the aid of a mold. It is then rapidly and uniformly quenched (tempered), creating safety glass with a specific radius of curvature.
I. Core Characteristics & Technical Value
1. Structural Safety & High Strength
- Inherits all safety properties of tempered glass: surface compressive stress ≥ 90 MPa, impact resistance 5-10 times that of annealed glass, and breaks into granular fragments.
- The curved structure provides enhanced stability in specific directions.
2. Design Freedom & Aesthetic Expression
- Can achieve complex 3D forms such as single curvature (cylindrical bend) and double curvature (spherical bend), breaking the visual limitations of flat glass.
- Perfectly aligns with modern architectural fluid design, creating seamless, continuous curved visual effects.
3. Process Irreversibility
-Shaping and tempering occur simultaneously. No modifications to the shape, cutting, or drilling are possible after the process.
- All holes, notches, and edgework must be completed before the heat-bending and tempering process.
Primary Applications: Architectural curved curtain walls, arched skylights, panoramic elevator cabs, curved glass railings, high-end furniture, automotive glass, appliance panels (e.g., curved TV backs), storefront displays, laboratory equipment, etc.
The thickness of curved tempered glass directly affects the minimum bend radius and forming difficulty.
* Note: The Minimum Bend Radius (R) is typically 100 to 300 times the glass thickness (t) [R=100t ~ 300t], depending on glass brand, equipment precision, and curve type.
2. Size & Shape Capabilities
Maximum Processable Size: Limited by bending furnace dimensions. Current advanced industry capabilities can reach:
①Single Curvature Glass: Longest side ≤ 5000mm
②Double Curvature Glass: Projected dimensions ≤ 3500mm x 2500mm
③Actual sizes are subject to factory capacity verification.
Shape Classification:
①Single Curvature (Cylindrical Bend): Curved in one direction only. Higher production efficiency, relatively lower cost.
②Double Curvature (Spherical/Compound Bend): Curved in two directions. Requires 3D molds, complex process, and high cost.
Tolerance Standards:
①Camber Height Tolerance: Typically ±2mm
②Chord Length Tolerance: Typically ±2mm
③Conformity (to mold/template): Gap usually required to be ≤ 3mm
Curved tempered glass can be formed from various base glass types, offering rich color options:
III. Key Technical Considerations
Mold Cost & Precision:
Each specific curvature requires a dedicated mold (steel or refractory material), leading to significant mold costs and long lead times (2-4 weeks).
During design, strive to standardize or minimize the number of curvature types to control costs.
Optical Distortion Control:
The bending process can introduce minor optical distortions (e.g., waviness). For visually critical applications like curtain walls, clear optical quality standards must be established and verified with physical samples.
Stress Distribution & the "Ball-Joint Effect":
Complex double curvatures can result in uneven tempering stress distribution. Support systems should employ multi-point or flexible supports to avoid hard connections that create localized stress points and potential breakage.
Installation Tolerances :
Setting blocks or framing for curved glass must provide larger installation gaps than for flat glass (typically recommended ≥ 6mm) to accommodate manufacturing/installation tolerances and thermal expansion.
IV. Procurement & Design Checklist
Drawing Requirements: Must provide detailed 3D digital models (e.g., Rhino, CAD) indicating key control dimensions (chord length, camber height, radius of curvature) and datum edges.
Provide Sample Mold/Template: For complex double-curved glass, strongly recommend providing a physical sample mold or contour template for factory verification.
Confirm Process Sequence: Establish the complete workflow: "Cutting → Edging/Drilling → Heat-Bending & Tempering → (Lamination/IGU Assembly)".
Order Physical Mock-ups: Before full production, it is essential to order full-size process samples to verify visual appearance, optical quality, and fit with installation interfaces.
Curved tempered glass is one of the most technologically advanced and aesthetically expressive categories in architectural glass. It represents the perfect fusion of safety and artistic form. The keys to successful application are: early design involvement to optimize curves and standardize specifications; deep collaboration with the manufacturer to confirm process feasibility; and rigorous quality control during the mold and sample stages. Selecting 5-6mm thickness with an Ultra-Clear substrate is a common starting point that balances performance, aesthetics, and cost, while any coating or double-curvature requirements will significantly increase the project's technical complexity and budget.